changing to next development version: 4.3.1-SNAPSHOT
RFPL-2800: Updated the atmosphere version in the developer guide
RFPL-2779: Fixed the a4j:push JMS integration example
Some corrections to the built-in sort/filter controls documentation
RFPL-2753: Added a migration notes appendix to the migration guide
changing version to 4.3.1.Final
Section titles updated

Titles of section updated to unify it with other sections, one typo fixed.
Initial generation of the Developer_Guide.asciidoc
Fixes to the xslt resulting in better asciidoc
Removed two files accidentally committed